c

# string que irá armazenar a cadeia de bases
s = 'CACTATGACTAAATCATTATGCTTACCTATAAGCGCCCCATAATCTGGTGGTCTCTTTAGCAAATTATGATATGCACGGGTGCATCCTGGAGCACCAATGACATCTTATGGACCCAGTCAATATAAGCTGCGGCAATACGAACTGTTCTTTCCGCGACACAACCCAATCGACAATTGTAAAGGGAGTCCTGGTCCGAAGGCTCAGGCGGTAAGGCTTGTTGATAATAAATGACGCTTTGTTTGAATACCATGCGGTCTGGGTTGTCGCGAACATCCCAACAGGAAATTAGCAGCGTCATCAAGGTGCAATCTGGTAAAGTCTAAGGTCAATAATGTTCATGTTAAGGTTGTCGCGGCAGTTGGGACGTTTTGGCGCTCACTTCATTGGTTTTTGAGAGGGTTTAGTATGATCCCGGTGCGGGGCCTGATGCAAAAAAAGATATGGGTAGTGGTCCCCTCTACTAGGGAGATGATTGAACGCGCGCCAAGGAAGCCTCGCTTTCTCAAATGGGAGTCTCTCTAAACTACTGAACTCAACGCCGGGGAGCGAGCATAGGGAGACCTTTCGTGTCTATTACCTTTTACAAAGATCGTGTTGATTCATTCTTTTTTAGGGTACAACGATCAATGGCCGAATTTATTCGGAGCTGTCCCCGCTTTCGGTGTCGACCCCCATCAAGTAGAGATTGGACTAAGAACCAAGGATAGGAGCATAGGGCTAGATTGTGTGTCTATTCCGTGGTATAATCATCAAAGTGGGAATTGAAGCAAAAAACATACGGAGTCACGGGTGATAGTGTAAGTTTCCATTGAACTGTCGTTGATGAGCTCCCAAAATACCATCGATGCGATCACTTCTGGCCGTCTCTGAGAGGTCATCCCGGGTCACCCCGGCCCC'

# string that will be the complement of the string s
s_c = ''

#generating the complement of the string s
for i in range(len(s)):

    if s[i] == 'A':
        s_c += 'T'

    elif s[i] == 'T':
        s_c += 'A'

    elif s[i] == 'C':
        s_c += 'G'

    elif s[i] == 'G':
        s_c += 'C'

#reversing the string
reverse = ''
x = 1
for i in range(len(s_c)):

    reverse += s_c[len(s_c) - x]
    x += 1


print(reverse)
# print(s)